Paper manufacturing is a major industry and a continuously growing one. Increased production of paper imposes a severe demand on plant raw material and thus harms the environment. Recycling of used paper is an alternative that can alleviate the stress that is exercised on the environment. The three major sources of raw material for such recycling are newsprint, photocopied paper and inkjet-printed papers. Recycling of paper requires the removal of the printing ink from the used paper, called deinking, so that the processed material is brighter. Printing on paper is accomplished by using two types of inks, the impact and the non-impact inks. In impact inks, used for newsprints, the ink does not fuse with the paper and is, therefore, easy to remove or disperse during the deinking, or recycling process. Such recycling is now well known and has been carried out for years. On the contrary, non-impact inks used in photocopying, ink-jet printing and laser printing results in the ink fusing with the paper and makes it non-dispersible, thus rendering the deinking process much more difficult (Jeffries, 2002). The toners used for photocopying generally contain iron oxide (about 55%0, olefins (about 5%) and plastic or polymer (Website:http://www.eng-tips.com).
Various hydrolytic enzymes such as cellulase, lipase, amylase of bacterial or fungal origin, individually or in combination have been used for deinking of office waste paper.                (i) A reference may be made to a publication wherein, a method for deinking of xerographic and printed paper, collectively called office waste, includes applying deinking solution to the paper to be deinked, the deinking solution being composed of a cleaning solution and a surfactant, abrading the paper to remove the ink from paper, and washing the paper to remove the deinking solution from the paper (U.S. Pat. No. 6,022,423 Bhatia, S. 1996 Method for deinking paper dated 2000-2, Aug.). However, this patent involves using a special device for deinking of whole sheets and cannot be used on pulp.        (ii) Another reference may be made to wherein, a monocomponent cellulase is used for removal of ink and toners from printed paper (U.S. Pat. No. 5,525,193 Neal, E., Steven, B. E., Hans, H. C. 1994. Use of monocomponent cellulase for removing inks, coatings and toners from printed paper). The technique of isolating monocomponent cellulase from microorganisms by various purifications, chromatographic steps is time consuming and expensive.        (iii) A reference may be made to a publication wherein, endogluconases and hemicellulases from several fungi are used effectively for deinking of Xerox and laser-printed paper (Gubitz, G. M., Mansfield, S. D., Bohm, D. Saddler, J. N. 1998. Effect of endoglucanases and hemicellulases in magnetic and flotation deinking of xerographic and laser-printed papers. Journal of Biotechnology. 65:209-215). As mentioned above the enzyme technology is still an expensive one for using on a large scale.        (iv) A reference may be made to a publication, wherein deinking of laser printed or xerographic paper is done using enzyme containing a resistant binder. Enzyme is added in the specified form to improve speck removal (Landley, J. G. Stockwell, J. O. 1997. Enzyme deinking of paper. Patent Number GB 2304741 dated 26 Mar. 1997). As with the above references, the technology to produce enzymes, their purification and application is an expensive process.        (v) A reference may be made to a publication, wherein deinking of office waste paper is carried out by contacting the pulp with a deinking agent containing enzymes cellulase, preferably active at pH 4 to 8. The treated paper is used in the production of newsprint and high quality paper (Jobbins, J. M. Asbrand, Jr. G. R. 1996. Composition and process for deinking office waste paper. Patent Number EP 717144 dated 19 Jun. 1996). As with the above references, the technology to produce enzymes, their purification and application is an expensive process.        (vi) A reference may be made to a publication, wherein deinking of waste paper is achieved by incubating the paper pulp with cellulase at 40° C. for 1 hour under pressure. Following dissociation of ink particles, the resulting washed pulp is brighter (Mitsubishi Heavy Industries. 1994. Deinking of waste paper. Patent number JP06346390 dated 20 Dec. 1994). As with the above references, the technology to produce enzymes, their purification and application is an expensive process.        (vii) A reference may be made to a publication, wherein deinking is achieved by using lipase to remove ink from used paper. The procedure is carried out under neutral or alkaline conditions which produces regenerated pulp having enhanced brightness (Novo. 1990. Removing ink from used paper. Patent number JP2160984 dated 20 Jun. 1990).        (viii) A reference may be made to a publication, wherein deinking of waste paper is done by using the yeast Hansenula polymorpha, which degrades the ink-based resin (Jeonju-Paper. 1993. Waste-paper deinking. Patent Number KR 9303705 dated 8 May 1993). However, the ink floats on the surface and the pulp has to be extensively washed to remove the detached ink.        (ix) A reference may be made to a publication, wherein decolorization of Indian ink is achieved by using thermostable alkaline cellulase from a Bacillus sp (Kao. 1998. A microbiologically produced thermostable alkaline cellulase and a process for its preparation. Patent number JP10313859).        